For example, a linear motor is frequently used in an exposure apparatus used in the production of semiconductor elements, liquid-crystal display elements and the like, as a drive device that can drive without contact a reticle stage wherein a mask (reticle and the like) is placed and held, or a wafer stage wherein a photosensitive substrate (wafer, substrate and the like) is placed and held. Although heat-releasing coil body is used in this kind of linear motor when current is passed, generally, the exposure apparatus is used under environments wherein the temperate is controlled to a steady value. Thus, the heat release is anticipated to be inhibited in this linear motor also. For example, the heat release from the linear motor may cause thermal deformation in the surrounding members and devices, and may vary the air temperature in the light path of an interferometer used for detecting the stage position, and cause errors in the measured values.
The coil body was housed in a cooling jacket, and a temperature regulating medium (coolant) was made to flow through the jacket, thereby disclosing the technology for absorbing heat generated in the coil body (for example, refer to patent document 1). This patent document 1 also discloses technology using pure water as the coolant.    [Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2003-86486.